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  • Handling update errors in multiple records in the TClientDataset's ReconcileError method

    - by Fabio Gomes
    I'm trying to use the ReconcileError event to allow the user to correct the data after an update error which occurred in a specific record among others. Example: I have a dataset with one field and 3 records, this field have a unique constraint on the database, then I change one value to conflict when it reaches the database, then I call ApplyUpdates on the Dataset. This will generate an error (violation of unique constraint) in the provider and abort the applyupdates process, returning raAbort in the Action var of the ReconcileError method. In the ReconcileError method I tryied to use: Action := HandleReconcileError(aDataSet, UpdateKind, E); ** EDIT ** After debugging and dumping the DataSet records which were returned from the server, I noticed that there are 2 records in this Dataset, the first is the Old record and the second have all the changes I made to the first record. I'm a bit confused, will I always get this DataSet with 2 records? I thought that it should have only one record with the Old/New values. Thanks.

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  • Select on multiple criteria with XPath

    - by Matt Thrower
    I have an XML document which looks something like this: <meadinkent> <record> <comp_div>MENSWEAR</comp_div> <sty_ret_type>ACCESSORIES</sty_ret_type> <sty_pdt_type>BELTS</sty_pdt_type> <pdt_category>AWESOME_BELTS</pdt_category> </record> <medinkent> I want to useXPath to select nodes which match all four elements and I'm having trouble getting the boolean syntax right. I'm trying this to match the first two just as a test: "/meadinkent/record/comp_div[.='" & comp_div & "'] and /meadinkent/record/sty_ret_type[.='" & sty_ret_type & "']" Which is failing, saying no nodes are returned. Obviously I'm being very stupid - what am I doing wrong? Cheers, mAtt

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  • How to dynamically choose two fields from a Linq query as a result

    - by Dr. Zim
    If you have a simple Linq query like: var result = from record in db.Customer select new { Text = record.Name, Value = record.ID.ToString() }; which is returning an object that can be mapped to a Drop Down List, is it possible to dynamically specify which fields map to Text and Value? Of course, you could do a big case (switch) statement, then code each Linq query separately but this isn't very elegant. What would be nice would be something like: (pseudo code) var myTextField = db.Customer["Name"]; // Could be an enumeration?? var myValueField = db.Customer["ID"]; // Idea: choose the field outside the query var result = from record in db.Customer select new { Text = myTextField, Value = myValueField };

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  • MySQL & PHP - select/option lists and showing data to users that still allows me to generate queries

    - by Andrew Heath
    Sorry for the unclear title, an example will clear things up: TABLE: Scenario_victories ID scenid timestamp userid side playdate 1 RtBr001 2010-03-15 17:13:36 7 1 2010-03-10 2 RtBr001 2010-03-15 17:13:36 7 1 2010-03-10 3 RtBr001 2010-03-15 17:13:51 7 2 2010-03-10 ID and timestamp are auto-insertions by the database when the other 4 fields are added. The first thing to note is that a user can record multiple playings of the same scenario (scenid) on the same date (playdate) possibly with the same outcome (side = winner). Hence the need for the unique ID and timestamps for good measure. Now, on their user page, I'm displaying their recorded play history in a <select><option>... list form with 2 buttons at the end - Delete Record and Go to Scenario My script takes the scenid and after hitting a few other tables returns with something more user-friendly like: (playdate) (from scenid) (from side) ######################################################### # 2010-03-10 Road to Berlin #1 -- Germany, Hungary won # # 2010-03-10 Road to Berlin #1 -- Germany, Hungary won # # 2010-03-10 Road to Berlin #1 -- Soviet Union won # ######################################################### [Delete Record] [Go To Scenario] in HTML: <select name="history" size=3> <option>2010-03-10 Road to Berlin #1 -- Germany, Hungary won</option> <option>2010-03-10 Road to Berlin #1 -- Germany, Hungary won</option> <option>2010-03-10 Road to Berlin #1 -- Soviet Union won</option> </select> Now, if you were to highlight the first record and click Go to Scenario there is enough information there for me to parse it and produce the exact scenario you want to see. However, if you were to select Delete Record there is not - I have the playdate and I can parse the scenid and side from what's listed, but in this example all three records would have the same result. I appear to have painted myself into a corner. Does anyone have a suggestion as to how I can get some unique identifying data (ID and/or timestamp) to ride along on this form without showing it to the user? PHP-only please, I must be NoScript compliant!

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  • SQL Server Clustered Index: (Physical) Data Page Order

    - by scherand
    I am struggling understanding what a clustered index in SQL Server 2005 is. I read the MSDN article Clustered Index Structures (among other things) but I am still unsure if I understand it correctly. The (main) question is: what happens if I insert a row (with a "low" key) into a table with a clustered index? The above mentioned MSDN article states: The pages in the data chain and the rows in them are ordered on the value of the clustered index key. And Using Clustered Indexes for example states: For example, if a record is added to the table that is close to the beginning of the sequentially ordered list, any records in the table after that record will need to shift to allow the record to be inserted. Does this mean that if I insert a row with a very "low" key into a table that already contains a gazillion rows literally all rows are physically shifted on disk? I cannot believe that. This would take ages, no? Or is it rather (as I suspect) that there are two scenarios depending on how "full" the first data page is. A) If the page has enough free space to accommodate the record it is placed into the existing data page and data might be (physically) reordered within that page. B) If the page does not have enough free space for the record a new data page would be created (anywhere on the disk!) and "linked" to the front of the leaf level of the B-Tree? This would then mean the "physical order" of the data is restricted to the "page level" (i.e. within a data page) but not to the pages residing on consecutive blocks on the physical hard drive. The data pages are then just linked together in the correct order. Or formulated in an alternative way: if SQL Server needs to read the first N rows of a table that has a clustered index it can read data pages sequentially (following the links) but these pages are not (necessarily) block wise in sequence on disk (so the disk head has to move "randomly"). How close am I? :)

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  • Import xml to database with high end performance and Audit log- A best Practice

    - by karthik
    Hi, I have to import big xml files to Ms SQL 2005 Database by using C# with high end Performance. Even if any record fails in middle, i have to take next record for process and failed record need to log for audit. I don't want to put insert query with in for loop. Could you please suggest a best way to do this. If I can use bulkcopy methods or Data Adapter update methods- Its very nice, But if any record fails, execution of that statement breaks and rolled back totally, right? Any alternatives and Best practices with example please..? Is Multi-threading works for me to improve performance..? Give me example please. Thanks Karthikeyan

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  • Any simple approaches for managing customer data change requests for global reference files?

    - by Kelly Duke
    For the first time, I am developing in an environment in which there is a central repository for a number of different industry standard reference data tables and many different customers who need to select records from these industry standard reference data tables to fill in foreign key information for their customer specific records. Because these industry standard reference files are utilized by all customers, I want to reserve Create/Update/Delete access to these records for global product administrators. However, I would like to implement a (semi-)automated interface by which specific customers could request record additions, deletions or modifications to any of the industry standard reference files that are shared among all customers. I know I need something like a "data change request" table specifying: user id, user request datetime, request type (insert, modify, delete), a user entered text explanation of the change request, the user request's current status (pending, declined, completed), admin resolution datetime, admin id, an admin entered text description of the resolution, etc. What I can't figure out is how to elegantly handle the fact that these data change requests could apply to dozens of different tables with differing table column definitions. I would like to give the customer users making these data change requests a convenient way to enter their proposed record additions/modifications directly into CRUD screens that look very much like the reference table CRUD screens they don't have write/delete permissions for (with an additional text explanation and perhaps request priority field). I would also like to give the global admins a tool that allows them to view all the outstanding data change requests for the users they oversee sorted by date requested or user/date requested. Upon selecting a data change request record off the list, the admin would be directed to another CRUD screen that would be populated with the fields the customer users requested for the new/modified industry standard reference table record along with customer's text explanation, the request status and the text resolution explanation field. At this point the admin could accept/edit/reject the requested change and if accepted the affected industry standard reference file would be automatically updated with the appropriate fields and the data change request record's status, text resolution explanation and resolution datetime would all also be appropriately updated. However, I want to keep the actual production reference tables as simple as possible and free from these extraneous and typically null customer change request fields. I'd also like the data change request file to aggregate all data change requests across all the reference tables yet somehow "point to" the specific reference table and primary key in question for modification & deletion requests or the specific reference table and associated customer user entered field values in question for record creation requests. Does anybody have any ideas of how to design something like this effectively? Is there a cleaner, simpler way I am missing? Thank you so much for reading.

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  • rails activerecord save method

    - by Yang
    hi, guys, can the save method be used to update a record? person = Person.new person.save # rails will insert the new record into the database. however, if i find a record first, modify it and save it. is it the same as performing a update? person = Person.find(:first, :condition => "id = 1") person.name = "my_new_name" person.save # is this save performing a update or insert? Thanks in advance!

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  • Java, dBase microsoft driver and deleted flag

    - by blow
    Hi, im connecting to dBase from java with this string: String url="jdbc:odbc:DRIVER={Microsoft dBase Driver (*.dbf)};DBQ="+databasePath+";DefaultDir="+databasePath+";DriverId=533;FIL=dBase IV;MaxBufferSize=2048;PageTimeout=5;"; Work fine, but with a SELECT statement i can retrieve only record that are not "deleted". In dBase database deletet record are only flagged deleted, so i want retrive deleted record too. Is this possibile? Thank.

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  • Generic object to object mapping with parametrized constructor

    - by Rody van Sambeek
    I have a data access layer which returns an IDataRecord. I have a WCF service that serves DataContracts (dto's). These DataContracts are initiated by a parametrized constructor containing the IDataRecord as follows: [DataContract] public class DataContractItem { [DataMember] public int ID; [DataMember] public string Title; public DataContractItem(IDataRecord record) { this.ID = Convert.ToInt32(record["ID"]); this.Title = record["title"].ToString(); } } Unfortanately I can't change the DAL, so I'm obliged to work with the IDataRecord as input. But in generat this works very well. The mappings are pretty simple most of the time, sometimes they are a bit more complex, but no rocket science. However, now I'd like to be able to use generics to instantiate the different DataContracts to simplify the WCF service methods. I want to be able to do something like: public T DoSomething<T>(IDataRecord record) { ... return new T(record); } So I'd tried to following solutions: Use a generic typed interface with a constructor. doesn't work: ofcourse we can't define a constructor in an interface Use a static method to instantiate the DataContract and create a typed interface containing this static method. doesn't work: ofcourse we can't define a static method in an interface Use a generic typed interface containing the new() constraint doesn't work: new() constraint cannot contain a parameter (the IDataRecord) Using a factory object to perform the mapping based on the DataContract Type. does work, but: not very clean, because I now have a switch statement with all mappings in one file. I can't find a real clean solution for this. Can somebody shed a light on this for me? The project is too small for any complex mapping techniques and too large for a "switch-based" factory implementation.

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  • Linking Access records to Excel files

    - by glinch
    Hi there, I've been trying to create a complete system using MS Access, but i really need to use the functionality of excel spreadsheets. I wish to do the following; when I create a record, i create a directory for that record, and copy an excel spreadsheet to that directory. The spreadsheet will be able to link to the corresponding record. So for example if I have a field 'Name' In the database record, the value of this field will show up on the excel spreadsheet. Is it possible to this?

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  • How do I apply a "template" or "skeleton" of code in C# here?

    - by Scott Stafford
    In my business layer, I need many, many methods that follow the pattern: public BusinessClass PropertyName { get { if (this.m_LocallyCachedValue == null) { if (this.Record == null) { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.PropertyId); } else { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.Record.ForeignKeyName); } } return this.m_LocallyCachedValue; } } I am still learning C#, and I'm trying to figure out the best way to write this pattern once and add methods to each business layer class that follow this pattern with the proper types and variable names substituted. BusinessClass is a typename that must be substituted, and PropertyName, PropertyId, ForeignKeyName, and m_LocallyCachedValue are all variables that should be substituted for. Are attributes usable here? Do I need reflection? How do I write the skeleton I provided in one place and then just write a line or two containing the substitution parameters and get the pattern to propagate itself? EDIT: Modified my misleading title -- I am hoping to find a solution that doesn't involve code generation or copy/paste techniques, and rather to be able to write the skeleton of the code once in a base class in some form and have it be "instantiated" into lots of subclasses as the accessor for various properties. EDIT: Here is my solution, as suggested but left unimplemented by the chosen answerer. // I'll write many of these... public BusinessClass PropertyName { get { return GetSingleRelation(ref this.m_LocallyCachedValue, this.PropertyId, "ForeignKeyName"); } } // That all call this. public TBusinessClass GetSingleRelation<TBusinessClass>( ref TBusinessClass cachedField, int fieldId, string contextFieldName) { if (cachedField == null) { if (this.Record == null) { ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), typeof(int) }); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, fieldId }); } else { var obj = this.Record.GetType().GetProperty(objName).GetValue( this.Record, null); ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), obj.GetType()}); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, obj }); } } return cachedField; }

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  • Should I expect Comet to be this slow?

    - by Chad Johnson
    I have the following in a Rails controller: def poll records = [] start_time = Time.now.to_i while records.length == 0 do records = Something.uncached{Something.find(:all, :conditions => { :some_condition => false})} if records.length > 0 break end sleep 1 if Time.now.to_i - start_time >= 20 break end end responseData = [] records.each do |record| responseData << { 'something' => record.some_value } # Flag message as received. record.some_condition = true record.save end render :text => responseData.to_json end and then I have Javascript performing an AJAX request. The request sits there for 20 seconds or until the controller method finds a record in the database, waiting. That works. function poll() { $.ajax({ url: '/my_controller/poll', type: 'GET', dataType: 'json', cache: false, data: 'time=' + new Date().getTime(), success: function(response) { // show response here }, complete: function() { poll(); }, error: function() { alert('error'); poll(); } }); } When I have 5 - 10 tabs open in my browser, my web application becomes super slow. Is this to be expected? Or is there some obvious improvement(s) I can make?

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  • Update Table in Asp.Net MVC

    - by Xulfee
    I have table on page i want to delete record from table and also update table after deletion record. <%= Ajax.ActionLink("Delete Ajax", "PostTypeDelete",new { id = item.int_PostTypeId }, new AjaxOptions{LoadingElementId="status"}) %> I used above code its working fine (it delete record) but it doesn't update table.

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  • MySQL :- select by month

    - by Pankaj
    how can i get record from table using month/year? I have a table like Project Name - varchar DueDate -datetime Status -boll DueDate is project due date, i want record corresponding to month/year,not full date, i mean record for specific month. How can i do this in mysql

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  • migrating from Prototype to jQuery in Rails, having trouble with duplicate get request

    - by aressidi
    I'm in the process of migrating from Prototype to jQuery and moving all JS outside of the view files. All is going fairly well with one exception. Here's what I'm trying to do, and the problem I'm having. I have a diary where users can update records in-line in the page like so: user clicks 'edit' link to edit an entry in the diary a get request is performed via jQuery and an edit form is displayed allowing the user to modify the record user updates the record, the form disappears and the updated record is shown in place of the form All of that works so far. The problem arises when: user updates a record user clicks 'edit' to update another record in this case, the edit form is shown twice! In firebug I get a status code 200 when the form shows, and then moments later, another edit form shows again with a status code of 304 I only want the form to show once, not twice. The form shows twice only after I update a record, otherwise everything works fine. Here's the code, any ideas? I think this might have to do with the fact that in food_item_update.js I call the editDiaryEntry() after a record is updated, but if I don't call that function and try and update the record after it's been modified, then it just spits up the .js.erb response on the screen. That's also why I have the editDiaryEntry() in the add_food.js.erb file. Any help would be greatly appreciated. diary.js jQuery(document).ready(function() { postFoodEntry(); editDiaryEntry(); initDatePicker(); }); function postFoodEntry() { jQuery('form#add_entry').submit(function(e) { e.preventDefault(); jQuery.post(this.action, jQuery(this).serialize(), null, "script"); // return this }); } function editDiaryEntry() { jQuery('.edit_link').click(function(e) { e.preventDefault(); // This should look to see if one version of this is open... if (jQuery('#edit_container_' + this.id).length == 0 ) { jQuery.get('/diary/entry/edit', {id: this.id}, null, "script"); } }); } function closeEdit () { jQuery('.close_edit').click(function(e) { e.preventDefault(); jQuery('.entry_edit_container').remove(); jQuery("#entry_" + this.id).show(); }); } function updateDiaryEntry() { jQuery('.edit_entry_form').submit(function(e) { e.preventDefault(); jQuery.post(this.action, $(this).serialize(), null, "script"); }); } function initDatePicker() { jQuery("#date, #edit_date").datepicker(); }; add_food.js.erb jQuery("#entry_alert").show(); jQuery('#add_entry')[ 0 ].reset(); jQuery('#diary_entries').html("<%= escape_javascript(render :partial => 'members/diary/diary_entries', :object => @diary, :locals => {:record_counter => 0, :date_header => 0, :edit_mode => @diary_edit}, :layout => false ) %>"); jQuery('#entry_alert').html("<%= escape_javascript(render :partial => 'members/diary/entry_alert', :locals => {:type => @type, :message => @alert_message}) %>"); jQuery('#entry_alert').show(); setTimeout(function() { jQuery('#entry_alert').fadeOut('slow'); }, 5000); editDiaryEntry(); food_item_edit.js.erb jQuery("#entry_<%= @entry.id %>").hide(); jQuery("#entry_<%= @entry.id %>").after("<%= escape_javascript(render :partial => 'members/diary/food_item_edit', :locals => {:user_food_profile => @entry}) %>"); closeEdit(); updateDiaryEntry(); initDatePicker(); food_item_update.js jQuery("#entry_<%= @entry.id %>").replaceWith("<%= escape_javascript(render :partial => 'members/diary/food_item', :locals => {:entry => @entry, :total_calories => 0}) %>"); jQuery('.entry_edit_container').remove(); editDiaryEntry();

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  • How to pass multiple different records (not class due to delphi limitations) to a function?

    - by mingo
    Hi to all. I have a number of records I cannot convert to classes due to Delphi limitation (all of them uses class operators to implement comparisons). But I have to pass to store them in a class not knowing which record type I'm using. Something like this: type R1 = record begin x :Mytype; class operator Equal(a,b:R1) end; type R2 = record begin y :Mytype; class operator Equal(a,b:R2) end; type Rn = record begin z :Mytype; class operator Equal(a,b:Rn) end; type TC = class begin x : TObject; y : Mytype; function payload (n:TObject) end; function TC.payload(n:TObject) begin x := n; end; program: c : TC; x : R1; y : R2; ... c := TC.Create(): n:=TOBject(x); c.payload(n); Now, Delphi do not accept typecast from record to TObject, and I cannot make them classes due to Delphi limitation. Anyone knows a way to pass different records to a function and recognize their type when needed, as we do with class: if x is TMyClass then TMyClass(x) ... ???

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  • How to reference a specific object in an array of objects using jTemplates

    - by Travis
    I am using the excellent jTemplates plugin to generate content. Given a data object like this... var data = { name: 'datatable', table: [ {id: 1, name: 'Anne'}, {id: 2, name: 'Amelie'}, {id: 3, name: 'Polly'}, {id: 4, name: 'Alice'}, {id: 5, name: 'Martha'} ] }; ..I'm wondering if it is possible to directly specify an object in an array of objects using $T. (I'm hoping there is something like $T.table:3 available) Currently the only way I can think of to access a specific object in an array is to do something like this... {#foreach $T.table as record} {#if $T.record$iteration == 3} This is record 3! Name: {$T.record.name} {#/if} {#/for} However that seems clumsy... Any suggestions? Thanks

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  • Constructor Injection and when to use a Service Locator

    - by Simon
    I'm struggling to understand parts of StructureMap's usage. In particular, in the documentation a statement is made regarding a common anti-pattern, the use of StructureMap as a Service Locator only instead of constructor injection (code samples straight from Structuremap documentation): public ShippingScreenPresenter() { _service = ObjectFactory.GetInstance<IShippingService>(); _repository = ObjectFactory.GetInstance<IRepository>(); } instead of: public ShippingScreenPresenter(IShippingService service, IRepository repository) { _service = service; _repository = repository; } This is fine for a very short object graph, but when dealing with objects many levels deep, does this imply that you should pass down all the dependencies required by the deeper objects right from the top? Surely this breaks encapsulation and exposes too much information about the implementation of deeper objects. Let's say I'm using the Active Record pattern, so my record needs access to a data repository to be able to save and load itself. If this record is loaded inside an object, does that object call ObjectFactory.CreateInstance() and pass it into the active record's constructor? What if that object is inside another object. Does it take the IRepository in as its own parameter from further up? That would expose to the parent object the fact that we're access the data repository at this point, something the outer object probably shouldn't know. public class OuterClass { public OuterClass(IRepository repository) { // Why should I know that ThingThatNeedsRecord needs a repository? // that smells like exposed implementation to me, especially since // ThingThatNeedsRecord doesn't use the repo itself, but passes it // to the record. // Also where do I create repository? Have to instantiate it somewhere // up the chain of objects ThingThatNeedsRecord thing = new ThingThatNeedsRecord(repository); thing.GetAnswer("question"); } } public class ThingThatNeedsRecord { public ThingThatNeedsRecord(IRepository repository) { this.repository = repository; } public string GetAnswer(string someParam) { // create activeRecord(s) and process, returning some result // part of which contains: ActiveRecord record = new ActiveRecord(repository, key); } private IRepository repository; } public class ActiveRecord { public ActiveRecord(IRepository repository) { this.repository = repository; } public ActiveRecord(IRepository repository, int primaryKey); { this.repositry = repository; Load(primaryKey); } public void Save(); private void Load(int primaryKey) { this.primaryKey = primaryKey; // access the database via the repository and set someData } private IRepository repository; private int primaryKey; private string someData; } Any thoughts would be appreciated. Simon

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  • Hibernate -using Table per subclass - how to link an existing superclass object to a sibclass object

    - by Chandni
    Hi, I have a User hibernate class, Clerk class and Consumer class. All these maps to their own tables in database. The User PK also acts as Clerk's and Consumer's PK. So now my problem is that if a user is initially a Clerk, he has a record in Users table and Clerks table. If that user wants to become a consumer, I want to link that User's record to the new Consumer's record. So even if I pass the userId to the consumer's record, it treats it as a new User to be persisted and gives a duplicate_key exception. How do I tell Hiernate to link the same user object with this new Consumer object. Thanks in advance, -Chandni

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  • Linq to Sql, Repositories, and Asp.Net MVC ViewData: How to remove redundancy?

    - by Dr. Zim
    Linq to SQL creates objects which are IQueryable and full of relations. Html Helpers require specific interface objects like IEnumerable<SelectListItem>. What I think could happen: Reuse the objects from Linq to SQL without all the baggage, i.e., return Pocos from the Linq to SQL objects without additional Domain Model classes? Extract objects that easily convert to (or are) Html helper objects like the SelectListItem enumeration? Is there any way to do this without breaking separation of concerns? Some neat oop trick to bridge the needs? For example, if this were within a repository, the SelectListItem wouldn't be there. The select new is a nice way to cut out an object from the Linq to SQL without the baggage but it's still referencing a class that shouldn't be referenced: IEnumerable<SelectListItem> result = (from record in db.table select new SelectListItem { Selected = record.selected, Text= record.Text, Value= record.Value } ).AsEnumerable();

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  • How can I do a right outer join where both tables have a where clause?

    - by cdeszaq
    Here's the scenario: I have 2 tables: CREATE TABLE dbo.API_User ( id int NOT NULL, name nvarchar(255) NOT NULL, authorization_key varchar(255) NOT NULL, is_active bit NOT NULL ) ON [PRIMARY] CREATE TABLE dbo.Single_Sign_On_User ( id int NOT NULL IDENTITY (1, 1), API_User_id int NOT NULL, external_id varchar(255) NOT NULL, user_id int NULL ) ON [PRIMARY] What I am trying to return is the following: is_active for a given authorization_key The Single_Sign_On_User.id that matches the external_id/API_User_id pair if it exists or NULL if there is no such pair When I try this query: SELECT Single_Sign_On_User.id, API_User.is_active FROM API_User LEFT OUTER JOIN Single_Sign_On_User ON Single_Sign_On_User.API_User_id = API_User.id WHERE Single_Sign_On_User.external_id = 'test_ext_id' AND API_User.authorization_key = 'test' where the "test" API_User record exists but the "test_ext_id" record does not, and with no other values in either table, I get no records returned. When I use: SELECT Single_Sign_On_User.id, API_User.is_active FROM API_User LEFT OUTER JOIN Single_Sign_On_User ON Single_Sign_On_User.API_User_id = API_User.id WHERE API_User.authorization_key = 'test' I get the results I expect (NULL, 1), but that query doesn't allow me to find the "test_ext_id" record if it exists but would give me all records associated with the "test" API_User record. How can I get the results I am after?

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  • Database nesting layout confusion

    - by arzon
    I'm no expert in databases and a beginner in Rails, so here goes something which kinda confuses me... Assuming I have three classes as a sample (note that no effort has been made to address any possible Rails reserved words issue in the sample). class File < ActiveRecord::Base has_many :records, :dependent => :destroy accepts_nested_attributes_for :records, :allow_destroy => true end class Record < ActiveRecord::Base belongs_to :file has_many :users, :dependent => :destroy accepts_nested_attributes_for :users, :allow_destroy => true end class User < ActiveRecord::Base belongs_to :record end Upon entering records, the database contents will appear as such. My issue is that if there are a lot of Files for the same Record, there will be duplicate record names. This will also be true if there will be multiple Records for the same user in the the Users table. I was wondering if there is a better way than this so as to have one or more files point to a single Record entry and one or more Records will point to a single User. BTW, the File names are unique. Files table: id name 1 name1 2 name2 3 name3 4 name4 Records table: id file_id record_name record_type 1 1 ForDaisy1 ... 2 2 ForDonald1 ... 3 3 ForDonald2 ... 4 4 ForDaisy1 ... Users table: id record_id username 1 1 Daisy 2 2 Donald 3 3 Donald 4 4 Daisy Is there any way to optimize the database to prevent duplication of entries, or this should really the correct and proper behavior. I spread out the database into different tables to be able to easily add new columns in the future.

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  • OO Objective-C design with XML parsing

    - by brainfsck
    Hi, I need to parse an XML record that represents a QuizQuestion. The "type" attribute tells the type of question. I then need to create an appropriate subclass of QuizQuestion based on the question type. The following code works ([auto]release statements omitted for clarity): QuizQuestion *question = [[QuizQuestion alloc] initWithXMLString:xml]; if( [ [question type] isEqualToString:@"multipleChoiceQuestion"] ) { [myQuestions addObject:[[MultipleChoiceQuizQuestion alloc] initWithXMLString:xml]; } //QuizQuestion.m -(id)initWithXMLString:(NSString*)xml { self.type = ...// parse "type" attribute from xml // parse the rest of the xml } //MultipleChoiceQuizQuestion.m -(id)initWithXMLString:(NSString*)xml { if( self= [super initWithXMLString:xml] ) { // multiple-choice stuff } } Of course, this means that the XML is parsed twice: once to find out the type of QuizQuestion, and once when the appropriate QuizQuestion is initialized. To prevent parsing the XML twice, I tried the following approach: // MultipleChoiceQuizQuestion.m -(id)initWithQuizRecord:(QuizQuestion*)record { self=record; // record has already parsed the "type" and other parameters // multiple-choice stuff } However, this fails due to the "self=record" assignment; whenever the MultipleChoiceQuizQuestion tries to call an instance-method, it tries to call the method on the QuizQuestion class instead. Can someone tell me the correct approach for parsing XML into the appropriate subclass when the parent class needs to be initialized to know which subclass is appropriate?

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